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well i feel that heat tape is good to use as a temporary measure and would use the self regulating type- frostex brand comes to mind… similar or same as mentioned above.. but if the pipes are directly attached to the backside of an interior heated wall , I would rearrange the insulation so it puts the pipes nearest the drywall on warm side of kneewall–or rather on the “warm” side of the insulation. more insulation would be needed to fully protect the pipes and to fully insulate this wall section……good luck.
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D
Just a thought, I would not rely on heat tape. Often times, especially in my area of the country, big snows bring cold temps and broken power lines. Without elec your heat tape is useless. I would wrap my pipes well and run a thin stream of water when it gets really cold
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Thanks for all the input guys. We bounced back up into the 40's and I have a few days grace to solve this problem.
I'm not anxious to use the heat tape because of the safety issue; and it's got to be plugged in; and it needs GFCI w/in 2 feet - no extension cords, etc, etc.
Extending room heat around the pipes seems most attractive. Fred's major change is not on the horizon. And David has identified an interior constraint.
ADDITIONAL INFO. The wall separating the unheated eave space where the pipes are located from room air is mostly blocked by the vanity and a closed clothes closet. Only about a foot of wall surface is directly exposed to the room. The house had originally been all electric radiant sheet rock heat. Installation of 2nd floor skylights disabled this system on 2nd floor. The forced air retrofit is on the ground floor only with no duct work to 2nd floor. 2nd floor is an occasional guest room and depends on supplemental electric heaters. In the room in question it's an electric hot air unit in the vanity kickspace immediately adjacent to the wall between room and eave space.
ADDITIONAL QUESTIONS. Say I build an insulated shell around weather side of pipes and eliminate insulation on the room side. I still can't count on anyone remembering to open the vanity & remove all those nice fluffy insulating towels or to pen the clothes closet. SO. Any suggestions on stealing heat from the kickspace unit, funneling it to the insulated shell? Or alternatively some sort of blower on a hole in that 1 foot wall space that would circulate room air?
TIA
Scott
*To get air through that vanity: how about a pipe (2-3" ABS or PVC) from the front or side of the vanty back into the bottom of that wall cavity and a return pipe or just an opening (little register) back into the room from that wall cavity. If you don't want to rely on the chimney effect to move the air, get the lowest wattage 120-volt computer cooling fan from Radio Shack ($10) or local computer dismantler ($1). They are quiet, plenty of air flow for one stud bay, and hardly any electrical draw. For the tiny register up high, I've seen 3 and 4-inch aluminum vents, louvered with bug screen inside for $4 at hardware stores and in Graingers'. Even during a power failure, you'd get some air circulation due to the chimney effect. -David
*Well, the search goes on guys. This guest bath room is pretty cool in unused periods and I'm not too confident about a natural chimney effect keeping the pipes warm if I passive vent the pipe space. There are hardwiring hurdles for fans and aestehtic concerns (the boss) about extension cords and visible STUFF.I've learned that both self-regulating and fixed resistance / thermostat controlled heat tapes are an NEC NoNo in enclosed spaces, and there's some question about what an eave space with a closet door is. A more practical concern is that self-regulating types never really shut off, and a seldom used line just warms and warms and warms creating a potential quick burst scald problem when the line is turned on. An upper limit switch is recommended, more complexity.Here's the latest. Know anything about Dampp Chaser, designed for closets and pianos? Waiting to hear from them about heat output but it might be just enough to boost the chimney effect through those little louvered vents.Here's the bonus. Even if this doesn't solve my frozen pipe problem, one intended application is for preventing rust in those humid basement and garage tool storage areas. http://www.damppchaser.com (maybe a hypen in there somewhere).Scott
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I have a question about frozen pipes. I'm not a contractor, but an insurance adjuster for a commercial insurance company. I handle construction defect claims.
I think I know the answer, but would like confirmation from those who know. If a pipe freezes and bursts, the water runs out because only a portion of the water in the line froze? I am told that if the temperature is 22 degrees then the water shouldn't be flowing out of the break. (I'm trying to help out one of our contractors who is being pursued by the homeowners insurance carrier).
Thanks in advance!
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Peggy,
I have no idea if the following is true, but I read it in FHB and it sounds plausible: the burst may not be caused by the expanding ice but by the water (non-compressable) being pressurized past burst strength by the expanding ice.
That's why letting the water trickle prevents a burst, the pressure can be relieved.
I would guess that there might be a timing issue. If the pipe bursts and all the water freezes at about the same time, then leak and damage will occur sometime later when things start to thaw.
Scott
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Scott, what is the FHB?
Thanks for your input.
Peggy
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Peggy,
It's shorthand for this board's sponsor, Fine Homebuilding magazine. The dynamics of a burst pipe are that the freezing water expands, exerting pressure throughout the system. The break, if it happens, may occur at a weak point well away from the frozen area, say a poorly sweated joint. If that's in a heated area, there'll certainly be water flowing. Leaving a tap dripping not only can provide a pressure relief, the moving water can help prevent the freezing in the first place.
Barry
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Here is another pipe-freezing related question. I designed my house so that all the plumbing is exposed in the stairwell to the basement, so it should never freeze. The well line comes in at 5' below grade to the basement. But the outdoor faucet is the only plumbing that goes into/thru an exterior wall.
I put a ball-valve inside the house, and turn it off then open the outdoor faucet, but the water does not fully come out, and the outdoor faucet freezes in the winter (Adirondacks - 8600 HDD, temps to -40F). Is there a type of outdoor faucet valve where the handle actuates a valve inside the house? Any other ideas?
Also, just curious, is there a type of pipe that can withstand freezing? Folks here would pay alot for that I would think.
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Scott: I've seen heated rods (usually brass-colored) for preventing mildew in closets. Just a low wattage resistance heater (20-100 watts) one to four feet long to add a little heat to a cold closet (into which some warm and humid room migrates and condenses). They are sold both for sailboats and for terrestial homes. A light bulb in the bottom of the closet would do the same thing, but with much higher surface temperatures, and therefore, less safety.
If you don't like electrons, there are moisture absorbing salts that come in a little (6-inch diamtere, 6-inch height) plastic holder. A upper mesh container holds the salt crystals in the air and a lower portion catches the drips. Every week or so, you drain off the brine and refill as needed. I've seen it in hardware store ($10?, $3/refill) and certainly in a boat supply store like West Marine. I don't know what salt is used. Anyone know? It is undoubtable available in bulk for less, possible as a sidewalk ice melting preparation.
But because of electrical and chemical costs, these methods are fine for closet but not for a garage. -David
*Richard,I had a similar situation where the sillcock was the frost free type: outside handle connected to a long valve stem so actual shut off was inside the house. Had double protection off a shut off with bleeder on the line to the fixture. Turned off the inside valve, bled the line and opened the outside line to let it drain. Somehow some water got trapped and the frostfree valve burst. When I replaced it I made sure there was positive drainage to the outside and the inside bleeder. A real safe practice is to blow the line out through the bleeder.Scott
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Thanks Scott - I'll replace it as you suggest. It is a bit of a surprise that only 8" of plumbing can be such a headache.
Thanks Again!
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They make those freeze-proof hose spigot valves in several lengths for different wall thicknesses, get the deepest one you can fit. I'm putting all mine through where an interior wall meets the exterior wall. So I can use very deep recessed valves and so I've got no standing water in any exterior walls. Glad to be warned by your experience - I'm now going to slope mine down at the very end to make it more positively draining.
I've got a dog musher friend who spec'd hot and cold freeze-proof recessed faucets (his 26 dogs get a hot gruel mixture each day and he can mix it all outside). Really nice to have a hot water spigot in the backyard for washing the dog, kids, and equipment!
A little heat tape, installed in advance and left accessible but unplugged can be a blessing when problems crop up. -David
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I have the outside faucet line up with the kitchen sink, so the valve could be way inside the cabinet, and repairs etc. dont muck up a finish wall.
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Update on my post above. Found those salt-based dehumidifiers at Fred Meyer's for $6.19 and the refill of crystals for $1.09 on sale. -David
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SITUATION. Hot and cold water supplies (1/2" copper) to a 2nd floor bathroom vanity run partially (about 5 feet) through an unheated eave space. The run fairly tightly against the eave space side of the insulated interior knee wall. The eave space is used for storage and (as seems inevitable with clutter) the usual stuff winds up next to the pipes. House heat is forced air.
It got down to 10F last night and they both froze, but fortunately did not burst. The main concern now is keeping them from freezing and bursting in the future.
QUESTIONS. The simplest solution seems to be an electric heat tape wrapped around the pipes. 1) How safe are they, particularly in such close proximity to combustible materials? 2) Should insulation be placed over the heat wrap? 3) Is a better long term solution to create an insulated air space around the pipes and circulate room air through it? 4) Any other suggest solutions, short of bringing the pipes into the room?
*The best solution would be to create an area where the ambient temperature is above freezing. In lieu of that, go ahead and use the heat tapes. Follow the manufacturers instructions for installation and insulate well. Wrap the heat tape around the pipe, don't just lay in out parallel to it. You want a sandwich of insulation, heat tape and then the pipe. The most common heat tapes are flat plastic tapes and are thermostatically controlled. Generally any failure in the thermostat is that it fails to turn on. Seldom do they stick in the on position and overheat. Be sure not to overlap the tape on itself when installing.A more expensive tape solution is to use a heat tape called WinterGard. It's made by Raychem. There are other manufacturers that make a similar product. This tape has a braided metal shield around it and is self regulating. If accidentally overlapped it won't burn out or overheat. It has the added advantage of being able to be cut to any length, whereas you have to buy the flat tape in a manufactured fixed length. If you can buy from Grainger, it's on p3303 of their Catalog 389. It's available in 3 watts/ft and 6 watts/ft. The 3w/f will handle pipes up to 2". As with other heating tapes, this must be insulated after installation.
*Thanks allaround. Since I posted my question I found http://www.clement.com/nltr/ssn1118.htm which provides guidelines from Consumer Product Safety Commission. The isulation over tape issue seems to be variable by maunfacturer.Still interested in other suggestions.
*well i feel that heat tape is good to use as a temporary measure and would use the self regulating type- frostex brand comes to mind... similar or same as mentioned above.. but if the pipes are directly attached to the backside of an interior heated wall , I would rearrange the insulation so it puts the pipes nearest the drywall on warm side of kneewall--or rather on the "warm" side of the insulation. more insulation would be needed to fully protect the pipes and to fully insulate this wall section......good luck.
*Along the same vein as Paul's suggestion: get the pipe in a location within the wall that is closer to room temperature than to the outside temperature. If you put high R-valve rigid foam between the pipe and the outside surface of the wall (nicely sealed with expanding foam) and minimal, if any, insulation inside of the pipe, the pipe will be much closer to the 65F inside temp than the minus whatever outside temp. No heat trace, no plug ins, etc. If the pipe has roughly equal insulation inside and out it ought to be good to about 0F outside temps. But if 80% of the insulation is outboard of the pipe, you could survive any outside temperature. If crap gets piled against that wall (adding undesirable insulation between the pipes and their only heat source) mount some stand-offs on the wall. So that even if crap gets piled against the wall, room air can circulate along the inner surface of the wall. -David